10 Longest Tunnel in the United States 2025

 10. Eisenhower Tunnel (CO) – 1.7 miles; high-altitude road tunnel in Rockies.

Longest Tunnel in the United State

 9. Anton Anderson Tunnel (AK) – 2.5 miles; shared road-rail tunnel to Whittier.

Longest Tunnel in the United State

 8. Cascade Tunnel (WA) – 7.8 miles; longest U.S. rail tunnel through Cascades.

Longest Tunnel in the United State

 7. Ward Tunnel (NY) – 9.5 miles; supports NYC’s water system.

Longest Tunnel in the United State

 6. Deer Island Tunnel (MA) – 9.5 miles; releases treated wastewater offshore.

Longest Tunnel in the United State

 5. Sudbury Aqueduct (MA) – 16 miles; historic Boston-area water conduit.

Longest Tunnel in the United State

 4. MetroWest Tunnel (MA) – 17.6 miles; modern water tunnel for Boston area.

Longest Tunnel in the United State

 3. Hultman Aqueduct (MA) – 17.8 miles; key Boston water delivery tunnel.

Longest Tunnel in the United State

 2. Quabbin Aqueduct (MA) – 25 miles; connects major reservoirs for Boston.

Longest Tunnel in the United State

 1. Delaware Aqueduct (NY) – 85 miles; world’s longest tunnel; supplies NYC water.

Longest Tunnel in the United State